The present invention relates to an apparatus for delivering large containers of goods, especially warehoused goods such as pallets, to an out-processing station or transfer station, and includes an inclined delivery segment that leads into the out-processing station and that has at least one conveyor means for moving the large containers.
When warehousing goods or similar articles it is generally customary to consolidate those goods that are small in volume in larger containers, these containers then being stored separately, for instance on racks or shelves. Large containers in the context of this invention are especially pallets, wire cages, boxes, and similar containers that are suitable for receiving a plurality of small articles.
When a certain number of articles that have been combined in large containers need to be removed from storage, it is necessary to remove the large container from storage, for instance from the rack, to open the large container, and to remove the desired number of articles that are to be taken out of storage. This process is also known as out processing, whereby the articles combined in the large containers are called warehoused goods.
Usually the large containers are delivered to an out-processing station for this purpose, at which station the actual out-processing is then performed manually or automatically.
Known during transport of large containers on pre-specified conveyor segments is providing transfer stations at which the containers are removed from a conveyor segment and forwarded for further transport for instance, on a different conveyor segment to another transport means, or are even forwarded by conventional transport means such as by truck.
Known in prior art is removing the large container from storage using appropriate aids, for instance an article handling apparatus, placing it on a delivery segment that leads into the out-processing station or transfer station, and then transporting it via transport means to the out-processing station or transfer station.
The gravity exerted by the large container itself can be used to move the large container along the delivery segment. Provided for this is a delivery segment that is inclined to the horizontal and that has a roller conveyor as transport means. The large container, such as a pallet, is first placed on the roller conveyor at the beginning of the delivery segment and, due to its own gravity, moves along the individual rollers of the roller conveyor in the direction of the out-processing station or transfer station to which the delivery segment leads. Once there, out-processing of the desired quantity of articles can begin, or the large container is transferred, as described above. In the case of out-processing, if the large container is completely emptied, it is removed from the out-processing station and another large container can be delivered along the delivery segment. The same applies when a transfer takes place.
Furthermore known is dimensioning the delivery segments such that above the out-processing station one or more large containers, such as pallets, can be set aside and which, once the large container located in the out-processing station or transfer station has been processed and removed or transferred out of the out-processing station, can be transported into the out-processing or transfer station, which is now unoccupied. The advantage of such a solution is that this system can realize the so-called first-in/first-out technique, in which a large container that is the first placed on the delivery segment is also the first to be out-processed or transferred. This is particularly important for articles with limited shelf-life, since, due to their limited shelf-life, care must be taken that the articles that are placed in storage first are the first to be removed from storage in order that a maximum tolerable period of time is not exceeded.
It has been determined that in particular in connection with palletized goods, there are particular problems associated with the delivery segments that have roller conveyors integrated therein and that work using gravity. The various commonly-used pallets (such as the Europallet or the GMA pallets conventionally used in the United States) are usually made of wood. When a pallet is in the transfer or out-processing station of the known apparatus that has roller conveyors, and if another pallet has been placed on the roller conveyor in a wait position, the weight produced by the palletized goods places a load on the wood forming the underside of the pallet that is in contact with the rollers of the roller conveyor. This causes the rollers of the roller conveyor to press into the relatively soft wood of the pallet. If the out-processing of the pallet that is in the out-processing station lasts for an extended period, or if the out-processing is interrupted by a break in work for an extended period (for instance, a weekend), or if the pallet remains in the transfer station for an extended period until it is transferred, the rollers of the roller conveyor can press relatively deep into the wood on the underside of the pallet. Then, if the pallet located in the transfer or out-processing station is emptied and/or removed, and if the next pallet set on the roller conveyor in the direction of the transfer or out-processing station is to follow, it is possible that the rollers of the roller conveyor have been pressed so far into the wood on the underside of the pallet that the pallet can no longer automatically move over the rollers of the roller conveyor. On the contrary, it can be retained in its position by the rollers that are pressed into the wood.
Instead of the pallet moving in the direction of the transfer or out-processing station due to its own gravity, as provided, additional measures must now be undertaken. In the worst case scenario, when even additional force exerted on the pallet does not release the pressed-in rollers of the roller conveyor from the underside of the pallet, the pallet must be at least partially out-processed then and there, i.e., on the delivery segment, so that it is possible to move the pallet in the direction of the transfer or out-processing station by removing weight from it.
Not only do such occurrences interrupt transfer or out-processing operations, they also tie up resources that have to be used to release the pallet that is stuck on the roller conveyor.
U.S. Pat. No. 5,350,270 provides one alternative to the roller conveyors described in the foregoing. This patent suggests using a cart that runs on an inclined track in order to move palletized goods along a delivery segment. The cart is formed by a frame and extends largely across the entire width of the delivery segment, which is approximately equal to the width of the pallet to be delivered. The cart has two axles with wheels, of which two run on a right-hand track and two run on a left-hand track. The problems associated with roller tracks that occur as described in the foregoing can be avoided with this known apparatus. However, since the cart extends across the entire width of the delivery segment and also across the entire width of the pallet, it is not possible with this solution to retrieve, using a transport device such as, for instance, a forklift on an article handling device, a pallet that is currently situated in the delivery segment and that was removed from the wagon and placed there. This is because such a forklift on an article handling device would be blocked by the cross-struts of the cart frame.
However, it is frequently necessary to remove, for instance, large containers that have been partially out-processed from an out-processing station and to return them to storage. It is desirable to perform this process in a manner that is as automated as possible.
Thus the object of the invention is to further develop a known apparatus such that large containers located in the delivery segment can be simply and advantageously returned with an article handling device.
To achieve this object, the invention suggests an apparatus for delivery of large containers of goods, in particular warehoused goods, to an out-processing station or transfer station, and comprises:
an inclined delivery station that leads to the out-processing station or transfer station, which delivery station has at least two tracks arranged essentially parallel leaving an intermediate space, and
at least two carts forming a cart pair, whereby each of said carts, which run on wheels, is arranged in one of the tracks for movement along the track; whereby said carts each have support or bearing surfaces, and whereby a large container can be placed upon the bearing surfaces of the cart pair.
Since, instead of a wide cart embodied across the entire width of the delivery segment, a cart pair is used that is arranged to leave a free intermediate space, the intermediate space or area thus available can be used to move in a transport means for retrieving a large container from the out-processing or transfer station or from the delivery segment. If a large container that has been introduced into the delivery segment for some reason must be removed therefrom, an article handling device with a forklift, for instance, can reach into the intermediate space between the tracks, take the large container, and convey it out of the delivery segment and back into a storage system, for instance. Such a design also minimizes the manual labor that has to be performed and enhances the flexibility of the facility.
In accordance with one advantageous further development of the invention, the apparatus has a stop or deposit device in the out-processing station or transfer station onto which a large container can be moved. The large container that has been brought to the out-processing station or transfer station is then moved from the cart onto the deposit device. The carts are thus then free to receive another large container.
In accordance with another advantageous further development of the invention, for moving the large container onto the deposit device, the bearing surfaces of the carts are each height-adjustable with respect to the distance to the wheels of the cart. In this manner the large container located on the bearing surfaces of the carts of the cart pair can be removed by lowering the bearing surfaces to the deposit device motion. In order to initiate lowering or raising of the bearing surface of the carts, the tracks can each have a stop at a first end and at a second end, which stops trigger a change in the distance between the bearing surfaces of the carts and their wheels when the carts strikes the stops. In accordance with an additional advantageous further development of the invention, for raising or lowering the surfaces of the carts, the carts can each have a base element on which the wheels are arranged and a carrier element that is displaceable relative to the base element and on which the bearing surface is arranged, whereby arranged on each of the base elements and carrier elements are slide members that are provided with inclined faces and that engage one another; displacement of the base element and carrier element relative to one another causes the height of the bearing surfaces to be adjusted. Such slide members are designed such that, when the carrier element or bearing surface is raised, the slide members lie against each other such that there is no displacement toward the lowered position. Displacement, and therefore lowering of the carrier element, due to mass inertia does not occur until the stop is struck.
In accordance with another advantageous further development of the invention, the tracks are formed by U-shaped profile tracks with a base and two legs arranged essentially perpendicular to said base, whereby the wheels of the cart run on the base. The cart located on this track is laterally guided by the legs due to the U-shaped embodiment of the tracks. The cart runs to some extent in a xe2x80x9cchannelxe2x80x9d in which it is guided optimally. In tracks thus embodied, a deposit device for a large container can be embodied simply by outwardly angled bevels in the legs. These bevels impart to the U-shaped profile additional stability against torsional moment, while they also form a simple and stable deposit device. For tracks embodied in this manner, the bearing surfaces of the carts, the height of which bearing surfaces can be adjusted between a lowered position and a raised position, should be embodied such that they lie below the bevels of the legs when in the lower position and above the bevels of the legs when in the raised position. In this manner the large container located on the bearing surfaces can be moved onto the bevels by simply lowering the bearing surfaces of the carts.
A single cart pair suffices if the inventive apparatus is to be embodied in a length appropriate for simultaneously receiving two large containers. A second cart pair is required for an apparatus embodied for simultaneously receiving three large containers. This cart pair also includes two carts, each of which has wheels and a bearing surface. The carts can each run on the tracks for the first carts; the tracks should be embodied larger as appropriate. In addition, second tracks for the second cart pair can be provided adjacent to the first tracks. The only critical factor is that the space left between each of the tracks for the first and/or second cart pair is sufficient so that a transport means, for instance a forklift on an article handling device, can penetrate into this intermediate space and retrieve a large container placed in the apparatus.
For an apparatus designed for three pallets with two cart pairs, in accordance with one advantageous further development of the invention it is provided that the height-adjustable bearing surfaces of the first cart pair are higher in their raised position than the bearing surfaces of the second cart pair in their raised position. In this manner, if both cart pairs are located in a starting position at the beginning of the delivery segment or at the beginning of the tracks, a large container can be moved onto the higher bearing surface of the first cart pair; the second cart pair remains undisturbed in the wait position at the beginning of the delivery segment. It is not until the first cart pair is not located in the wait position at the beginning of the delivery segment that a large container can be moved onto the raised bearing surfaces of the second cart pair and conveyed together therewith in the direction of the out-processing or transfer station.
In order to return the carts to a starting position after moving the large container out of the out-processing or transfer station, these are connected to a retrieval means that exerts a force on the carts in the direction away from the out-processing or transfer station, which retrieval means returns the carts without large containers placed thereupon to the starting position at the beginning of the track. This retrieval means can be, for instance, a spring, preferably a helical spring, that is connected to the beginning of the track at one end and to the cart at the other. Potential retrieval means include general energy-accumulating apparatus, such as, for instance, a rubber band, or retrieval means operated by means of accumulation of electrical energy. However, the retrieval means can also be weights connected to the carts via cable means, said weights being suspended from the tracks via a reverse at the upper end of the tracks. In this case the weight of the weights is used as the retrieving force.
The incline of the delivery segment, and thus of the tracks, should be selected depending on the carts used such that the weight of the large container on the components arranged parallel to the delivery segment is sufficient to overcome the friction between the carts and the tracks as well as the friction of the bearings of the wheels on the carts and to produce a weight-actuated drive in the direction of the out-processing station or transfer station. Care must be taken that the component of the weight in the direction of the delivery segment or tracks does not become so great that the large container being transported reaches an excessive speed. Otherwise this could lead to damage to the goods in the large container if there is abrupt braking. In order to be able to transport large containers of different weights in the inventive apparatus, as the invention suggests, it is advantageous for the incline in the tracks to be adjustable by incline adjustment means. Such incline adjustment means can be, for instance, spring-elastic compressable supports on the higher starting end of the tracks. These give more when large containers that are heavy are placed on the carts at the beginning of the tracks than when those large containers that are not as heavy are placed thereupon, so that less of an incline is set for large containers that are heavy than for large containers that are lighter in weight. In this manner largely uniform, moderate transport speed can be achieved when the spring-elastic compressable supports are designed appropriately.